Centrifugal casting apparatus with chill mold holding furnace

ABSTRACT

This composite equipment for the continuous manufacture of metal tubes, especially cylinder liners of internal combustion engines, according to the centrifugal casting method, comprises a rotary centrifugation tray carrying a plurality of centrifugation devices each receiving a centrifugation chill mold and registering by turns with a fixed station for loading the empty chill molds, with a casting station and with a fixed unloading station. Said trays 22 is driven for intermittent rotation and said loading and unloading stations constitute single station. A fixed dressing station is disposed angularly just downstream of this single station, and the casting station is supplied from a fixed source of molten metal.

United States Patent 1 Fauquembergue et al.

[73] Assignees: Regie Nationale Des Usines Renault,

Billancourt, Automobiles Peugeot,

Paris, both of FraiiEe [22] Filed: Nov. 15, 1971 [21] Appl. No.: 198,891

[30] Foreign Application Priority Data Nov. 26, 1970 France 7042528 [52] US. Cl 164/295, 164/286, 164/326, [64/338 [51] Int. Cl B22d- 13/10 [58] Field of Search 164/286, 326, 295, 164/337, 335, 154, 327, 328, 338; 425/435 [56] References Cited UNITED STATES PATENTS 2,023,040 Adams Saives 164/293 [451 July 31, 1973 2,943,368 7/1960 Peras 1. 164/295 3,267,531 8/1966 Buttkereit et a! 164/326 X 2,635,310 4/1953 Morgan 164/327 X FOREIGN PATENTS OR APPLICATIONS 565,040 10/1958 Great Britain 164/295 Primary Examiner-Robert D. Baldwin AttorneyRichard K. Stevens, Davidson C. Miller et al.

[ 5 7 ABSTRACT This composite equipment for the continuous manufacture of metal tubes, especially cylinder liners of internal combustion engines, according to the centrifugal casting method, comprises a rotary centrifugation tray car rying a plurality of centrifugation devices each receiving a centrifugation chill mold and registering by turns with a fixed station for loading the empty chill molds, with a casting station and with a fixed unloading station. Said trays 22 is driven for intermittent rotation and said loading and unloading stations constitute single station. A fixed dressing station is disposed angularly just downstream of this single station, and the casting station is supplied from a fixed source of molten metal.

8 Claims, 10 Drawing Figures Patented July 31, 1973 6 Sheets-Sheet 1 Patented July 31, 1973 6 Sheets-Sheet 2 mm cw mm mm Patented July 31, 1973 6 Sheets-Sheet f5 Patented July 31, 1973 3,749,153

6 Sheets-Sheet 4 Patented July 31, 1973 6 Sheets-Sheet 5 Patented July 31,- 1973 6 Sheets-Sheet 6 CENTRIFUGAL CASTING APPARATUS WITH CHILL MOLD HOLDING FURNACE The present invention relates to a composite workshop equipment designed for the continuous centrifugal casting of cylinder lines of internal combustion engines by means of centrifugation devices comprising each a chill-mold carrier adapted to contain and assemble the two half chill-molds. This equipment further comprises on the other hand a rotary centrifugation tray plate or spider comprising a plurality of radially disposed centrifugation devices, each adapted to receive a centrifugation chill mold, said devices registeringby turns with a fixed loading station for the empty chill molds, a casting or pouring station and a fixed discharge station, and on the other hand a chill-mold transfer track extending from a fixed station for picking up the filled molds, through a fixed station for extracting or stripping and discharging the cast liners.

In a prior U.S. Pat. No. 2.727.288, there is disclosed a centrifugal casting device implementing half-molds maintained in their closed or assembled condition during the casting operation, notwithstanding the clearance left between the centrifugation cylinder and said chill molds, by inertia weights and levers acting upon said half chill molds in order to compensate the effects produced by the thermal expansion and the centrifugal force on the half-molds and also on the metal cast therein.

Another U.S. Pat. No. 2.943.368 discloses an equipment for the continuous manufacture of cylinder liners by means of the device described in the patent mentioned in the preceding paragraph. This equipment comprises a circular tray constantly revolving at a uniform speed, whereby a plurality of centrifugation devices each adapted to receive a centrifugation chillmold are conveyed successively to a fixed loading station where said devices receive empty chill-molds, to a casting station and to a fixed discharge station. The same equipment comprises transport circuits leading from the discharge station, through a device for removing or ejecting the cast liners, to a station where the empty chill-molds are dressed or treated and thence to the loading station of the transport device. The rotary tray carries the centrifugation devices and each one of these devices is provided at the loading station with a chillmold carrier adapted to contain and fasten an empty two-section mold, and upon completion of the mold filling step, the chill-mold carriers can be removed from these devices at the discharge station at the same time as the filled molds for depositing them upon a chill-mold carrier transfer circuit. This lastnamed circuit is also used for transporting chill-mold carriers containing empty molds to the loading station via a station adapted to separate the filled molds from the chill-mold carriers. This chill-mold circuit leads in succession, beyond the liner stripping station, from a stripped-liner discharge ramp, from a conditioning area for the chill-molds to be coated, and also from a surface dressing station, to a re-molding station also connected to the chill-mold carrier circuit. This station is provided upstream of the loading station for introducing the chill molds adapted to be re-used into the chill-mold carrier travelling in the chill-mold carrier circuit.

The casting device according to the abovementioned U.S. Pat. No. 2.727.288 is objectionable in that it is not capable of bringing into precise alignment the axis of rotation and the axis of the half-mold assembly. As a result, the inner and outer walls of the liners are more or less eccentric, whereby an extra thickness must be provided, this obviously increasing the per centage of machining scrap. This eccentricity was caused by a faulty operation of the inertia weights; therefore, some novel centrifugal casting means has to be devised, as described and illustrated in the U.S. Pat. application Ser. No. 172,005 filed Aug. 16, 1971, now U.S. Pat. No. 3,710,848 and assigned to a common assignee.

In this last device, as illustrated in FIGS. 1 and 2 of the attached drawings, the heavy, separate configuration cylinder is replaced by a cylindrical frame struc ture rigid with the driving mechanism and the bent arms carrying the rollers and inertia weights are disposed in a certain angular relationship whereby the apex of the angle thus formed is pivoted to the cylindrical frame structure in the vicinity of the half-molds, so as to provide a half-mold assembly characterized by an automatic dynamic centering feature.

It was an obvious idea for the Applicants to modify the equipment disclosed in the U.S. Pat. No. 2.943.368 with a view to use the above-described device and thus simplify considerably the molding equipment while reducing its initial cost and the personnel necessary for its operation, and improving its working conditions and the final efficiency, therefore the production rate of the equipment.

These objects are attained by resorting to the improved equipment constituting the subject-matter of the present invention. Generally of the type mentioned at the beginning of the above preamble, the equipment according to the present invention is characterized in that the rotary tray is driven discontinuously by means of intermittent feed means, that the fixed stations for loading the empty chill molds, discharging and removing the filled chill molds, are merged into a single station and that a fixed station for dressing the chills fitted in the centrifugation devices is disposed angularly and immediately downstream of the single station, while the casting station proper is supplied with molten metal from a fixed source, said molten metal being kept at a constant temperature.

Advantageously, a fixed station for adding alloying component substances such as ferro-silicon is provided in proper registering relationship to the outer periphery of said rotary tray, angularly and immediately downstream of the fixed chill dressing station.

in a preferred form of embodiment, the casting sta tion comprises a pivoting casting tray or turnstile driven for intermittent rotation in synchronism with the centrifugation tray, said casting tray carrying cups for introducing the molten metal into the chils, said cups being supplied with molten metal from said fixed source.

Advantageously, this molten metal supply takes place through tilting ladles disposed on the casting tray, a casting or pouring beak or spout of said fixed source being located substantially vertically above the path followed by the openings of said ladles.

The direct introduction of the chills into the centrifugation devices, i.e. without resorting to the chill-mold carriers described in the aforesaid U.S. Pat. No. 2.943.368, makes it possible to provide a single station combining into one all the fixed stations of the prior art, designed for loading the empty chills, discharging stripping, separating the chills and their carriers, disposing fresh chills on said carriers, etc.., thus affording a considerable reduction in the total transfer path of the chills. with this reduction, any device for keeping the empty chills at a. proper temperature during the operation of the equipment can be dispensed withv The intermittent rotation of the centrifugation tray permits of utilizing a rotary casting tray of which the cups are supplied with molten metal from a fixed source. The chills can be dressed directly during their rotation about their axes in the centrifugation device, thus providing the additional advantageous feature of filling the joint plane, while facilitating the direct introduction of alloying component substances into the chills.

The various advantages described hereinabove play an essential part in the simplification of the equipment while reducing the manpower necessary for its operation, improving-the working conditions and increasing the output rate.

This invention comprises not only the general features set forth hereinabove but also certain details of the practical embodiment thereof, which are a direct outcome of said features. A clearer understanding of the present invention will be had as the following description proceeds with reference to the accompanying drawings illustrating diagrammatically by way of example a typical form of embodiment thereof. In the drawmgs FIGS. 1 and 2, already mentioned hereinabove are a longitudinal sectional view and a cross-sectional view, respectively, of a centrifugation device permitting the direct introduction of the half-molds FIGS. 3 and are perspective diagrammatic views of the complete equipment FIG. 4 is a plane view of the equipment FIG. 5 shows in front elevational view the single station for loading the empty chills, discharging and removing the filled chills FIG. 6 is a side elevational view of the single station FIG. 7 is a plan view from above of the single station FIG. 8 is a part-sectional view of the fixed station for extracting and discharging the cast liners, the section being taken along the line VIIlVlIl of FIG. 4; and

FIG. 9 is a section taken along the line IX-IX of FIGS. 4 and 8 to illustrate the liner extraction and discharge station.

A centrifugation device permitting the direct introduction of the mold-forming half-chills is illustrated by way of example in FIGS. 1 and 2. This device was disclosed in the US. patent application filed on Aug. 16, l97l.

The mold proper comprises two halves or half-chills l, 2 assembled along broken joints 3, 4. The bore 5 of the half-chills l, 2 corresponds to the outer diameter of the cylinder liners to be cast, and their length is such that tubes 29 can be cast and subsequently cut into a predetermined number of liners.

At one end, for example the right-hand end as seen in FIG. 1, ie opposite to the molten metal pouring end orifice 6, the assembled half-chills comprise an internal circular groove 7 adapted to retain in position a deflector washer 8 separating the cast liner tube 29 from the excess metal collected in a so-called priclter chamber As illustrated in FIG. 2, the outer surface of said halfchills 1 and 2 is not cylindrical but comprises four fiat faces 12 engageable by rollers to be described presently.

The assembled mold halves 1 and 2 are engaged by axial sliding movement and with a certain clearance into the inner space of a cylindrical frame structure or centrifugation barrel 13, as illustrated in FIG. 1.

This barrel 13 is a light-weight construction assisting in reducing the weight of the rotary centrifugation tray 22 supporting it. It comprises four identical angle members 14 of a length substantially equal to that of said half-chills 1 and 2; these angle members 14 are disposed with their concavity facing outwards and their apices directed towards the axis of rotation X-X' of the half-chills. The angle members 14 are rigidly assembled by means of a plurality of steel rings 15. The wings of said angle members 14 also act advantageously as efficient ventilation means. Surrounding the cylindrical structure thus constructed is a balancing device comprising a ball ring 16.

The centrifugation cylindrical frame structure 13 is rotatably driven by means of a transmission comprising for example a belt 17 disposed between the output pulley 18 of a motor 19 and another pulley 20 incorporated in a ventilated adjustable friction coupling 21, this device being protected by a casing 30.

The assembly comprising the cylindrical frame structure 13 and the drive thereof is connected to the centrifugation tray 22 through an elastic suspension 23 having an oscillation frequency considerably lower than the velocity of rotation of said centrifugation bar rel 13.

Two shafts 24 supporting bent levers 25 are mounted perpendicularly to the wings of angle members 14. Each shaft 24 extends through a point located at the apex of an acute angle formed by the bent lever 25. The arms of this lever have unequal lengths, the longer arm carrying an inertia weight 26 and the shorter one a cylindrical roller 28 bearing against one of the outer fiat faces 12 of the half-chills 1 and 2.

The levers 25 carrying the inertia weights 24 and rollers 28 are disposed at spaced intervals about the halfchills, to form groups of four levers each. One of these groups is disposed substantially at mid-length of the halfchills and the other two are located one at the front and the other at the rear thereof.

In the exemplary form of embodiment illustrated notably in FIGS. 3 and 4, the centrifugation tray 22 carries six pairs of centrifugation barrels l3 spaced at regular angular intervals.

Each pair of barrels is operated simultaneously. Therefore, the tray 22 is driven to accomplish successive 60 angular movements. The chill loading and unloading orifices as well as the orifices for introducing the molten metal into said chills are directed substantially radially inwards. Under these conditions, the centrifugation tray is supplied from, and surrounded by, in the direction of rotation, a single fixed station 31 for loading the empty chills 1 and 2 or 42, discharging or picking-up the filled chills 32, a fixed dressing station 33, a fixed station 34 where the alloying substances are added, and a pouring or casting station proper 35, these stations being spaced 60 from each other, the centrifugation operation proper taking place during the travel of the centrifugation barrels 13 carrying the filled chills 32 between the casting or pouring station 35 and the single station 31, i.e. in the sector of tray 22 opposite to the dressing and addition stations 33 and 34.

A detailed description of these stations 33 and 34 is not deemed necessary, for they constitute very simple devices well known per se.

The first device may be similar to that illustrated in FIGS. 90 and 9b of the above-mentioned US. Pat. No. 2.943.368. In this case it comprises two guns 36 for projecting under pressure the dressing liquid (silicate or like substance), said guns being mounted on a carriage 37 of which the automatic reciprocation permits of introducing the guns into the two chills. A control distributor (not shown) is adapted to be actuated by a stud (also not shown), one of these two elements being fixed and the other rigid with the carriage 37 so as to release a jet of dressing product in both directions of travel of the guns 36.

The other station 34 comprises two automatic powder dispensing and metering devices comprising each a hopper loaded with pulverulent FeSi containing 75 Si. At the base of this hopper a compressed-air gun is provided for introducing Fe Si into the chills.

The casting station 35 comprises a casting tray 38 driven for intermittent rotation and this tray has pivotally mounted thereon four tilting ladles 39 each formed with two pouring spouts or beaks overlying a funnel shaped pouring cup 40. Each one of the four groups comprising each one ladle 39 and two cups 40 is mounted on a carriage permitting of introducing at the proper time the beaks or spouts of the two cups into the openings of a pair of chills.

The discontinuous drive of the centrifugation and casting trays 22 and 38 is synchronized so that the casting tray 38 performs one-and-a-half revolution for each revolution of tray 22.

The tilting ladles 39 are supplied with metered quantities of molten metal from a single stationary heatmaintaining furnace 41.

As illustrated in FIGS. 1, 2 and 5 to 7, the single fixed station 31 for unloading the filled chills 32 and discharging the empty chills 42 is disposed in a rectilinear transfer path 43 comprising two superposed levels 44 and 45 for the chills. Each level comprises a roller conveyor driving in opposite directions guided supporting plates 46 provided with rollers 47 facilitating the axial sliding travel of the empty chills 43 and filled chills 32.

From the single station 31 the rectilinear transfer path 43 leads firstly to a station 48 for extracting and removing the molded liners 49, then through a lowering device 50 transfering the empty chills 42 to the lower roller conveyor 45 feeding these chills to a lifting device 51 depositing same upon the upper roller conveyor 44, upstream of the single station 31.

This single station 31 illustrated more in details in FIGS. 5, 6 and 7 comprises a carriage 52 adapted to slide across the transfer path 43 on a pair of fixed guide bars 53 of a frame structure 54 overlying the upper roller conveyor 44 at the location whereat, when the centrifuga tion tray 22 is stopped, the axes 55 of a pair of centrifugation barrels 13 extend at right angles to the path of the upper roller conveyor 44.

Since its reciprocating motion is controlled through a cylinder and piston unit 56, the carriage 52 carries a pair of clamps 57 actuated in turn by other cylinder and piston units 58, the axes of the openings of these clamps being coincident with the axes 55, whereby the carriage 52 can grip the end of a pair of filled chills 32 projecting from the barrels 13 and pull same out from said barrels for subsequently releasing these filled chills 32 on a pair of supporting plates 46 then driven away from the single station 31 by conveyor 44, and eventually grip a pair of empty chills 42 brought by this conveyor and push these empty chills into the two centrifugation barrels, whereafter the tray 22 is rotated through an angle of 60.

FIGS. 8 and 9 illustrate the fixed station 48 for extracting and removing the cast liners 49 downstream of the single station 31. It comprises essentially a chill opening and closing device 59, a liner extraction device 60 and a removing device 61.

The opening and closing device 59 comprises a lifting member consisting of a pivoting support 62 provided with a counter-balance weight 63 and responsive to a cyliner and piston unit 64; this support 62 is mounted in a frame structure 65. The lifting member also comprises an upper sliding gripping plate 66 guided in said support 62 and adapted to be moved from an upper position to a lower position and vice-versa by means of a cylinder and piston unit 67 when the support is lowered to its horizontal position.

The plate 66 designed for opening or closing simultaneously three chills comprises three pairs of upper pivoting claws 68 actuated by cylinder and piston units 69 and so disposed that on the plate 66 in its lower position the hooks of each pair of claws register with one another and lie exactly under the upper portion of the edges of the two apertures of a chill mold 32, the action of units 69 then permitting of assembling the plate 66 and the three upper half-chills 1 of a set of three chills 32 brought under the plate 66 by the conveyor 44. Studs 70 and corresponding or matching receiving sockets and abutment members 71 are provided on the pivoting support 62 and frame structure 65 for retaining said support 62 when the three upper half-chills l are detached.

The corresponding claws 72 of the three pairs of lower claws (also actuated by means of cylinder a piston units 73) are disposed symmetrically in relation to the upper claws 68 when the pivoting support 62 is lowered, said lower claws being mounted on either side of the roller conveyor 44 and mounted on a lower clawsupporting plate 74 disposed horizontally and guided in a horizontal table 75 of frame structure 65. For a purpose to be explained presently, another cylinder and piston unit 76 for raising and lowering the lower plate 74 as well as the conveyor rollers disposed in the fixed station 48 for extracting the liners is provided.

The extraction and removing devices 60 and 61 for the cast liners 49 comprise a guided carriage 77 movable in the horizontal direction, across the roller conveyor 44, and this carriage comprises three parallel horizontal extraction spindles 78 extending in overhanging relationship towards the chill opening and closing device 59, the axes of said spindles 78, which are contained in the vertical planes of claws 58 and 72, being level with the uppr portion of the cavities of liners 49 contained in chills 32 when the actuator 76 has moved the lower plate 74 and the corresponding conveyor rollers to their upper position.

The carriage 77 adapted to roll on rails 79 is driven from a rotary motor 80 adapted to drive in either direction of rotation a wheel 81 provided with a pneumatic riage 77, as shown.

The spindles 78, adapted on the one hand to extend through the three continuous liners 49 in chills 32 brought to their upper position in the opening device 59 and on the other hand to retain these liners by stripping same from the lower half-chills 2 when the cylinder and piston unit 76 lowers the bottom claw plate 74 together with these half-chills, are rigidly held during this operation since at one of their ends horizontal studs 85 rigid with the carriage 77 are adapted, in the operative position of this carriage, to engage corresponding retaining sockets 86 provided on the frame structure 65 and the opposite or leading ends of these spindles 78 engage other retaining sockets 87 also provided on said frame structure 65.

It may be noted that the fixed extraction and removing station 48 also acts as a preparation (re-molding) station for chills 42, as far as the positioning, before closing these chills, of the deflector washers 8 in the grooves 7 of said chills, the half-chills 2 being in this case in the upper position 88 corresponding to the general level of roller conveyor 44.

The discharge device proper 61 consists of a stop member 89 preventing the liners 49 carried by spindles 78 from moving backwards, so that as the spindles 78 recede or move to the left (FIG. 8) they emerge from the liners 49 and these are thus allowed to drop upon an inclined ramp or chute 90 leading into a handling cntainer 91 (FIG. 9).

An inclined through 92 leading to a container or vessel (not shown) is disposed beneath the ends 93 consisting of the solidified overflow contained in the chill pricker chamber 9. Under normal operating conditions these ends 93 should separate automatically from the liners. However, in case cast-iron burrs or the like prevented this separation from occurring normally, the liner tubes 49 are retained by groups of three between the ramp 90v and the upper retaining member 94 by means of a stop arm 95 actuated by a cylinder and piston unit 96. Three actuators 97 having each their piston rod provided with a push member 98 are secured to the frame structure 65 above the location of the three ends 93 so that if anyone of these ends happened to adhere to the liners proper said push members 98 would apply thereto a shock of a force sufficient to break them off.

Finally, the equipment according to this invention advantageously comprises a holding furnace 99 adapted to keep the chills 42 at the proer temperature during the hold-up periods of the equipment. This furnace comprises one or a plurality of roller conveyors 100, and another, overhead conveyor 101 provided with clamps is provided for depositing the chills 42 picked up from the lifting device 51 at theend of transfer path 44 onto said overhead conveyor 101. The latter is also adapted to transfer the chills in the opposite direction when the casting cycle is resumed (FIGS. 3, 4 and Most of the equipment operation is performed automatically.

The control diagram of this equipment is not shown or described since it is within the current knowledges of those skilled in the art and entrusted with the automatic control of this equipment. Of course, as new conventional in production lines of this type, the completion of an operation or run, or the completion of the production path by a member adapted to control this operation, will control the next operation by using any suitable apparatus and means such as limit switches and distributors, relays, solenoid-operated valves, etc...

As clearly apparent from FIG. 10, the manual action required is limited to the control of the furnace 41 for filling the ladies, and also to the positioning of the deflector washers 8 (FIG. 8), together with a simple supervision of the fixed station 48 for extracting and removing the liners.

The operation of the above-described equiment will now be described with reference to FIG. 10.

The empty chills 42 delivered by lifting device 51 are dircted by the upper roller conveyor 44 in the direction of the arrow towards the single discharge and removing station 31 where two chills are gripped by clamps 57 and introduced into the pair of centrifugation barrels 13 from which a pair of filled chills 32 have just been discharged by the same means.

Then, a rotation in the direction of the arrow will cause the centrifugation tray 22 to present the next pair of barrels l3 in'front of station 31 add the pair of empty, justpositioned chills to be placed in front of the dressing station 33.

During the next 60-degree rotation following the dressing step the two barrels put the chill openings in alignment with the addition station where a suitable predetermined metered dose of ferro-silicon is introduced into said chills.

Another 60 rotation will bring the openings of both chills in front of the beaks or spouts of the pair of casting or pouring cups 40 of which, at this moment, the support is fed forwards under the control of a cylinder and piston unit, until the beaks penetrate somewhat into said openings. Another actuator willthen cause the tilting ladle 39 located behind said cups to pivot and be discharged into the chills through the medium of said cups.

The chill rotation subsequently causes the cylinder liners to be molded by centrifugation, the pair of barrels involved registering again, after three successive 60 rotations of the centrifugation tray 22, with the single loading and unloading station 31 whereat the filled chills 32 containing the set liners are gripped by the clamps 57 and deposited upon the conveyor 44 so as to be directed towards the liner extraction and removing station 48.

Considering the fact that the centrifugation tray is fed step by step, each time through 60, it is obvious that the above-described cycle is repeated in'the same fashion for all the pairs of centrifugation barrels 13 mounted on said tray 22. Of course, each time the tray 22 is moved angularly through 60, the casting tray 38 perfonns one-fourth of a revolution in orderto cause a fresh, filled ladle to register with the next pair of barrels.

When three filled chills have been introduced and stopped into the frame structure of station 48, the three spindles of the liner extraction device 60 are introduced into the liners and the upper and lower halfchills are gripped by the upper and lower claw plates, respectively, these plates being subsequently moved away from each other to release the continuous liners enclosed in said chills. During the time the liners are retained by the discharge device 61 directing them towards the handling vessel 91 after the useless overflow ends of the cast tube have been detached from the liners proper, as described hereinabove with reference to FIGS. 8 and 9, the three lower liners are raised again to the level of the upper roller conveyor 44, and new deflector washers are fitted therein by the operator, and the upper claw plate is pivoted and lowered to deposit the upper half-chills upon the lower half-chills. Once released from the claw plate, the three empty half-chills ready for use are again carried along by the upper roller conveyor 44 and directedtowards the low ering device 50 from which they are transferred to the lower conveyor 45 and deposited thereby upon the raising device 51, whereafter the cycle continues as described hereinabove,

It is only during a temporary hold up of the equipment operation that the empty chills are removed at the level of raising device 51 by means of the overhead conveyor 101 provided with adequate clamps, in order to lay them upon the end of conveyors 100 penetrating into the holding furnace 99. Thus, the chills are left in this furnace throughout the hold-up time, thereby avoiding any loss of time and material as observed in case of reheating when resuming the working cycle. Without this furnace, the reheating of cold chills would take place at the expenses of the cast tubes, since these tubes would have to be junked on accunt of the hardening effect thus produced which would prevent the machining thereof.

What is claimed as new is 1. Apparatus for the continuous manufacture, by centrifugal casting, of cylinder liners of internal combustion engines by means of centrifugation devices comprising each a chill-mold carrier adapted to contain and assemble the two halves constituting a chill mold, comprising a rotary centrifugation tray carrying six pairs of parallel centrifugation barrels disposed at 60 degree intervals, each adapted to receive a centrifugation chill mold,

said pairs of barrels registering by turns with a fixed loading station for the empty chill molds, a fixed dressing station for dressing the chill molds housed in the centrifugation barrels which is located angularly and just downstream of said loading station, a casting or pouring station and a fixed discharge station whereby the two chill molds of one pair are loaded simultaneously into said barrels, treated, filled with molten metal, centrifugated and discharged,

intermittent means for discontinuously driving said centrifugation tray between said stations,

said fixed loading station and said fixed discharge station being merged into a single station which has two clamps to remove each chill mold,

said casting station being fed from a fixed source of molten metal.

a chill-mold transfer track extending from said single station to a fixed extracting station for extracting or stripping and discharging the cast liners,

said transfer track being substantially tangent to said centrifugation tray and comprising a pair of superimposed rectilinear roller conveyors leading at each end to a lifting device and to a lowering device whereby a closed chill mold circuit is obtained, and

means for maintaining the chill molds at a heated temperature during hold up periods in the operation comprising a furnace with at least one conveyor therein and a connecting conveyor equipped with a movable element provided with clamps to transfer empty chill molds from said transfer track to said conveyor in said furnace.

2. Apparatus according to claim 1 wherein a fixed alloying substance adding station means is positioned in registration with the periphery of said centrifugation tray, angularly and downstream of said dressing station for adding alloying substances such as ferro-silicon to said chill molds.

3. Apparatus according to claim 2, wherein said alloying substance adding station comprises at least one hopper constituting a reservoir of additive which is provided at its lower end with a compressed-air gun for introducing said additive into the chill molds.

4. Apparatus according to claim 1, wherein said casting station comprises a pivoting casting tray driven for intermittent rotation, said casting station and said centrifugation tray being driven in synchronism, said casting station carrying at spaced angular intervals a plurality of funnel-shaped cups having a lower horizontal beak for introducing molten metal into the chill molds, said cups being fed from a fixed source of molten metal through the medium of tilting ladles disposed on said casting tray, a pouring spout of said fixed source adapted to be tilted being located substantially vertically above the path of the openings of said ladles, each tilting ladle and the cup or cups fed therefrom being mounted for radial sliding movement on said casting tray to permit the introduction of the cup beaks into said chill mold openings.

5. Apparatus according to claim 1, wherein the single station comprises at least one clamp for introducing the chill molds into the centrifugation barrels and for removing said chill molds therefrom, said clamp being adapted to slide transversely in relation to said transfer track at the location where, during the stoppages of said centrifugation tray, the axes of said centrifugation barrels extend perpendicularly to said transfer track, the axis of the opening of said clamp being coincident with the barrel axis, the movements of translation of said clamp and the closing movement thereof being controlled by cylinder and piston means.

6. Apparatus according to claim 1, wherein the fixed extracting station comprises a chill mold opening and closing device comprising an upper claw plate adapted to be raised and a lower claw plate adapted to be lowered, the pivoting claws of said plates being actuated by cylinder and piston means and so disposed that they are adapted to grip at their ends, respectively, and to separate, the upper half-chills from the lower half-chills carried along by said upper conveyor of said transfer track, the rollers incorporated in said extracting station being adapted to move bodily with the lower claw plate in vertical translation, said fixed extraction station fuather comprising comprising a guided carriage movable in the horizontal direction and perpendicularly to the roller cenveyor, said carriage comprising parallel horizontal extraction spindles directed in overhanging relationship towards the chil mold opening and closing means, the axes of said spindles contained in the vertical planes already containing the claws and the axes being level with the upper portion of the cavities of liners contained in said chill molds when the lower plate fixed source of molten metal, are controlled automatically, and wherein a detector responsive to the arrival at a predetermined point of a given member causes the actuation of the member performing the next operation.

8. Apparatus according to claim 7, wherein one fraction of the members of the equipment are controlled by means of a programmed control system.

I i III I 

1. Apparatus for the continuous manufacture, by centrifugal casting, of cylinder liners of internal combustion engines by means of centrifugation devices comprising each a chill-mold carrier adapted to contain and assemble the two halves constituting a chill mold, comprising a rotary centrifugation tray carrying six pairs of parallel centrifugation barrels disposed at 60 degree intervals, each adapted to receive a centrifugation chill mold, said pairs of barrels registering by turns with a fixed loading station for the empty chill molds, a fixed dressing station for dressing the chill molds housed in the centrifugation barrels which is located angularly and just downstream of said loading station, a casting or pouring station and a fixed discharge station whereby the two chill molds of one pair are loaded simultaneously into said barrels, treated, filled with molten metal, centrifugated and discharged, intermittent means for discontinuously driving said centrifugation tray between said stations, said fixed loading station and said fixed discharge station being merged into a single station which has two clamps to remove each chill mold, said casting station being fed from a fixed source of molten metal. a chill-mold transfer track extending from said single station to a fixed extracting station for extracting or stripping and discharging the cast liners, said transfer track being substantially tangent to said centrifugation tray and comprising a pair of superimposed rectilinear roller conveyors leading at each end to a lifting device and to a lowering device whereby a closed chill mold circuit is obtained, and means for maintaining the chill molds at a heated temperature during hold up periods in the operation comprising a furnace with at least one conveyor therein and a connecting conveyor equipped with a movable element provided with clamps to transfer empty chill molds from said transfer track to said conveyor in said furnace.
 2. Apparatus according to claim 1 wherein a fixed alloying substance adding station means is positioned in registration with the periphery of said centrifugation tray, angularly and downstream of said dressing station for adding alloying substances such as ferro-silicon to said chill molds.
 3. Apparatus according to claim 2, wherein said alloying substance adding station comprises at least one hopper constituting a reservoir of additive which is provided at its lower end with a compressed-air gun for introducing said additive into the chill molds.
 4. Apparatus according to claim 1, wherein said casting station comprises a pivoting casting tray driven for intermittent rotation, said casting station and said centrifugation tray being driven in synchronism, said casting station carrying at spaced angular intervals a plurality of funnel-shaped cups having a lower horizontal beak for introducing molten metal into the chill molds, said cups being fed from a fixed source of molten metal through the medium of tilting ladles disposed on said casting tray, a pouring spout of said fixed source adapted to be tilted being located substantially vertically above the path of the openings of said ladles, each tilting ladle and the cup or cups fed therefrom being mounted for radial sliding movement on said casting tray to permit the introduction of the cup beaks into said chill mold openings.
 5. Apparatus according to claim 1, wherein the single station comprises at least one clamp for introducing the chill molds into the centrifugation barrels and for removing said chill molds therefrom, said clamp being adapted to slide transversely in relation to said transfer track at the location where, during the stoppages of said centrifugation tray, the axes of said centrifugation barrels extend perpendicularly to said transfer track, the axis of the opening of said clamp being coincident with the barrel axis, the movements of translation of said clamp and the closing movement thereof being controlled by cylinder and piston means.
 6. Apparatus according to claim 1, wherein the fixed extracting station comprises a chill mold opening and closing device comprising an upper claw plate adapted to be raised and a lower claw plate adapted to be lowered, the pivoting claws of said plates being actuated by cylinder and piston means and so disposed that they are adapted to grip at their ends, respectively, and to separate, the upper half-chills from the lower half-chills carried along by said upper conveyor of said transfer track, the rollers incorporated in said extracting station being adapted to move bodily with the lower claw plate in vertical translation, said fixed extraction station fuather comprising comprising a guided carriage movable in the horizontal direction and perpendicularly to the roller cenveyor, said carriage comprising parallel horizontal extraction spindles directed in overhanging relationship towards the chi l mold opening and closing means, the axes of said spindles contained in the vertical planes already containing the claws and the axes being level with the upper portion of the cavities of liners contained in said chill molds when the lower plate and the corresponding conveyor rollers are in their upper positions, a stop member beinG disposed in the backward path of the liners extracted by the spindles from said chill molds, whereby as they continue their backwrd movements said liners are removed from said chill-molds drop upon an inclined ramp leading into a handling container
 7. Apparatus according to claim 1, wherein the greater part of the component elements of the apparatus which perform each specific operation, except the fixed source of molten metal, are controlled automatically, and wherein a detector responsive to the arrival at a predetermined point of a given member causes the actuation of the member performing the next operation.
 8. Apparatus according to claim 7, wherein one fraction of the members of the equipment are controlled by means of a programmed control system. 